Motor Car Express Lube

I pulled into your parking lot and was met by a gentleman. I asked him a few questions which he answered. SHowed him a coupon for $8 off and he said give it to the cashier when the work is done. When the work was done the bill came to $150, which was fine for what was done. I paid him, then remembered the coupon. He said it was too late. When I asked if he was sure, he asked the guy that did the work and he said it was too late. The cashier said I could use it next time and I handed it back to him. I've worked in and owned a # of retail businesses and never heard of a policy like that. Poor business practice. you lost a new customer.